TEMPO-Catalyzed Electrochemical Dehydrogenative Cyclocondensation of o-Aminophenols: Synthesis of Aminophenoxazinones as Antiproliferative Agents

Aminophenoxazinone core is widely prevalent in natural products, dye and pharmaceutical molecules. We report here a TEMPO-catalyzed electrosynthetic method allowing the dehydrogenative cyclocondensation of o-aminophenols. This mild and sustainable method proceeds in the absence of stoichiometric oxidants and uses an easily available organo-electrocatalyst to access pharmaceutically valuable 2-aminophenoxazinones. Mechanistic studies indicate that the electrochemically generated TEMPO+ enables the oxidative radical homo-dimerization of o-aminophenols. The application of electrosynthesis provides an approach to pseudo-aminophenoxazinone alkaloids with improved structural diversification and bioactivities.